Amplifiers such as operational amplifiers are used in many electronic circuits to condition, manipulate and amplify signals. In general, an operational amplifier is designed so that the output signal of the amplifier is proportional to the difference between two input signals. While some operational amplifiers may be designed for a wide range of applications, others are designed for specific applications. For example, some may be designed for relatively high-voltage supplies to provide output signals with large voltages. Along operating with high-voltage applications, some designs may also be tailored for relatively fast-switching applications. Such high-power, fast-switching operational amplifiers may be implemented with discrete components and/or with hybrid circuitry. Such implementations call for considerable layout space and production cost.
In addition to a need for faster-switching, increased slew rate (i.e., maximum rate at which the output voltage of the operational amplifier can change) is desirable. However, slew rate may be constrained by the amount of current drawn by the operational amplifier during periods of inactivity. This quiescent current may be significant in high-power operational amplifiers. By reducing quiescent current, quiescent power dissipation may be lowered and operational amplifier performance may increase.